Numerous hormonal methods for contraception are known, i.e., the oral administration of combination-type preparations, e.g., "Ovulen", "Anovlar", "Lyndiol" and similar combinations of estrogenic and gestagenic active agents. Also conventional is the administration of purely sequential preparations, such as, for example, "Ovanone", etc., wherein first an estrogen is administered at a high dosage in the absence of gestagen, over a period of 7 days, and thereafter the estrogen is administered at the same high dosage in combination with a relatively high amount of gestagen over a period of 15 days, with the next 6 days being a blank period without administration of estrogenic or gestagenic agent in order to mimic the normal 28-day menstrual cycle of the woman.
The administration of modified sequential preparations is likewise conventional, such as, for example, "Kombiquens", "Tri-Ervonum" and "Oraconal", etc., wherein first an estrogen is administered at a high dosage in combination with a low amount of gestagen over a period of 16 days, and subsequently the estrogen is administered over a period of about 7 days at the same high dosage in combination with an amount of gestagen about 5-10 times the original amount. See U.S. Pat. No. 3,568,828. To adapt to the natural 28-day cycle of the female, a five-day hormone-free period follows the administration of these preparations wherein placebos or any desired other non-contraceptive effective agents are taken, such as, for example, tonics, iron supplements, etc.
It is also known to administer two-stage combination-type oral contraceptives, with a combination of an estrogen at a low dosage and a progestogen at a low dosage first being administered for 10-12 days and subsequently a combination of the same dosage of estrogen and a dosage of progestogen increased to 2-3 times as much, is ingested for 11-9 days. To adapt to the normal about 28-day female cycle, a 5-7 day hormone-free period follows in which no estrogens or progestogens are ingested. For continuity of dosage, a placebo or a nonhormonal effective agent is usually administered during this period. See application Ser. No. 350,590, filed Apr. 12, 1973.
Disadvantages inherent in the administration of the aforementioned pure and modified sequential products involving the administration of relatively high doses of estrogen, are, in addition to the usual symptoms due to excessive estrogen, e.g., gastrointestinal disturbances, nausea, weight gain with formation of edema, etc., an increase in the risk of thromboembolic disease. These disadvantages would be avoided by the administration of the above-described two-stage combination contraceptives, but in the latter it is desirable to improve the compatibility and/or the control of the cycle.
In application Ser. No. 486,757, filed July 9, 1974, there is claimed a contraceptive method in which a low but contraceptively effective daily dosage of an estrogen and a progestogen are administered for 10-12 days and thereafter a combination of an estrogen and a progestogen are administered at slightly higher dosages.